Art of decorating vitreous ware.



UNITED STATES Patented October 18, 1904.

PATENT OFFIcEij 7 ROBERT KENNEDY DUNCAN, OF WASHINGTON, PENNSYLVANIA- ART OF DECORATING VITREOUS WARE.

SPECIFICATION forming part of Letters Patent No. 772,876, dated October 18, 1904.

Application filed February 2, 1904:.

T0 011% whom it may concern:

or letters on articles, and more particularly toan improvement upon that for which Letters Patent were granted to me on the 5th day of January, 1904, and designated by No. 748,850.

' The object of my present invention is to provide for the adjustability of the fusibility of the material with which the designs, &c.,

are made, according to the temperature of the article when the said material is applied thereto. s r i I With this object in view the invention consists in certain novel steps in the method of decorating vitreous ware, as hereinafter set forth, and pointed out in the claim.

' The improved material, which I have designated as lead subborate, is made by fusing at a low temperature a mixture of a compound oflead, such as litharge or red lead or lead nitrate, with boric acid, either fused or crystalline, orthe material can be made by precipitation. I have used all of the above substances and have ascertained that they are preferably used in approximately the following proportions: litharge, (PbO,) 111.5, or red lead, (Pb30i,) 113.8, or lead nitrate, Pb (NO3)2,'165.5, mixed with boric acid, crystalline, (H3BO3,) thirty-one, or boric acid, fused, (13203,) 17.5. These substances mixed in the foregoing equivalent proportions yield an identical result with this exception, that when lead nitrate is used the color of the resulting product is somewhat improved.

Instead of using only one of the lead compounds referred to two of them may be mixed and used with advantagefl Thus a mixture may be employed which consists 'of lead nitrate, 17 .5, litharge, one hundred, and boric Serial No. 191,748- (No model.)

acid, (crystalline,) thirty-one. The lead subborate produced by the fusion of any one of th'eseseveral mixtures consists of a transparent highly refractive yellow-tinted glasslike mass and almost colorless in thin layers. It has, however, an extraordinary power of dissolving coloringmaterialsas, for example, metallic oxidsand the resultant may then present. a very beautiful color. These coloring materials may be mixed with a batch of the lead subborate before fusion, or they may be mixed with the powdered borate and then fused therewith, or they may be mixed with the lead subborate as it lies fused in the pot. j

The amount and kind of coloring-matter that is employed will depend on the kind and depth of color that may be desired. For example, the following proportions may beused forthe production of blue ornamentation or lettering: litharge, one hundred and twelve; horic acid, thirty-four; cobalt carbonate, 2. 6; nickel oxid, 0.1, For the production of emerald-green ornamentation, figures,or letters the following proportions may be employed: lead nitrate,

165.5; boric acid, thirty-three; cupric oxid,

3:2, and chromium oxid, 0.08.

Other colors-such as black, claret, copper,

&c.-may be. produced by using suitableinorganic oxide and salts. To produce an opaque enamel, the lead subborate is mixed with the oxide of antimony, arsenic, tin, &c., in the proper proportions. enameling substances with the coloring substances an opaque colored enamel is produced. For example, the oxidsof copper and cobalt mixed with the oxid of arsenic in the proper proportions will produce a turquoise enamel.

By very careful heating of the lead subborate it is possible to make it take the enamel condition without the necessity of adding any of the enameling-oxids, such as antimony, arsenic, &c'.

Anyone of the above-named mixtures of lead subborate and coloring material is put By mixing the into a crucible which is highly refractory, and the crucible is then heated to a degree as low of a low red heat. The fused mixture is poured from the crucible in a thin stream into cold water, with the result that it quickly sol idilies and is transformed into a granulated powder. The granular powder is drained and dried and is then reduced to a line impalpablc powder in an agate mortar or by means of a mill employing agate rollers. The use of an iron mortar or iron rollers is objectionable, because the hard borate would under such conditions take up enough of the iron to ruin its color. Hence a mortar or rollers made of agate or equivalent material should be employed for this purpose.

The lead sub orate is vitreous, transparent, and brilliant. It is capable of being rendered non-transparent or enamellil e. It is practically insoluble in hot or cold water. Its coefficient of expansion and contraction is approximately the same as glass, so that when applied it will not break or crack to pieces. It has the power of dissolving metallic oxids and salts to produce any desired colors. It unites chemically'with glass and causes the designs or letters to be securely and. permanently united therewith. it is capable of being removed from the glass. It is comparatively inexpensive to manufacture and may be applied at slight cost and without materially delaying the ordinary process of manufacture, and it is capable of fusion at a temperature not higher than the maximum temperature of the leers of annealing-ovens.

The preferred proportions of lead oxid and boric acid for the production of lead subberate are such as will contain the maximum quantity of lead to boric acid that is to say, about 111.5 oflead oxid to thirty-one of crystallized boric acid or 17.5 of melted boric acid. If the proportion of lead is increased beyond that above stated, it comes down in the metallic condition, and hence would be useless for the purpose set forth. By increasing the proportions stated of boric acid the compound is rendered less fusible; but the proportion may be increased to some extent above the proportion stated without rendering the compound too infusible for the purpose stated. Hence I do not restrict myself to the precise relative proportions stated, as they may be varied within certain limits and yet insure the desired result.

In the manufacture of glass articles as, for instance, glass bottles--the glass is blown or pressed into molds. In the case of blown Ware the intervals between the molding of the articles are of some duration. In the smallest pressed ware they come out of the molds at, say, a maximum rate of about ten a minute. The ware of all kinds isinvariably taken from the. molds while still red-hot in spots.

The lead subborate, owing to its low fusibility. instantly melts when placed in contact with glass that is barely red-hot and is applied to the bottle or other article immediately after itis removed from the mold, with the result that it melts and unites with the surface of the article. It has been found, however, that the temperature of the ware at the time the decorations are placed thereon will vary according to the character thereof that is to say, whether the ware is blown or pressed and whether it is liint, opal, &e. For this reason it is important to adjust the fusibility of my improved decorating material in 'order that it can be properly applied to the ware when the latter has a certain temperature at the time at which the material is to be applied to said ware. To accomplish this, I add to the material a substance which will render it less fusible, and the quantity of this substance (small in any case) can be readily determined by the known temperature of a certain kind of ware at that part of the process of making the same when it is most desirable to apply the decorating material. There are various substances which might constitute such agovernor such, for instance, as baryta.

The material may be applied to the ware by the use of stencil-plates or in any other desired manner. The comminuted material upon contact with the hot ware will quichly melt and produce the lettering or design formed of a smooth, brilliant, vitreous surface, the outlines of which are maintained sharp and clearly cut by the walls of the stencil-plate, as the material will not How after the stencil shall have been removed, especiallywhen the fusibility of the material has been properly governed, as before explained.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The herein-described method of decorating vitreous ware,'consisting in depositing upon a heated vitreous article, a compound resulting from the chemical reaction of boric acid and lead oxid, each in the proportion sub stantially as specilied and adding to said compound before application thereof to the heated article, a substance regulating the fusibilitv of the said compound according to the temperature of the vitreous article to be decorated.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

ROBERT KENNEDY DUNCAN.

\Vitnesses:

ALvAx Douuax, MINNIE A. LuoNAm). 

